1. Field of the Invention
The roller disc assembly of the present invention is intended for mounting on the underside of a platform, such as a shoe, to enable the platform to move either in forward/backward, circumferential, lateral or stationary rotational directions.
2. The Prior Art
In the roller skate art, a variety of locomotion mechanisms have been proposed. For instance, U.S. Pat. No. 1,975,661 discloses a pair of large-diametered disc-like wheels attached to a skate platform. Each wheel is set at an angle of less than 45 degrees with the surface on which it is intended to roll. Wheel movement permits the skate or other platform to travel in a linear forward or backward direction.
U.S. Pat. No. 3,885,804 describes a skate comprising a sole plate, boot and two large, canted, equal-sized wheels mounted upon axles extending outwardly from the sole plate. Undue strain and discomfort to the skater's ankles were said to be eliminated by placement of the wheel tire below the center line of the sole plate and by positioning plate close to the ground. Unfortunately, this wheel assembly has neither lateral nor circumferential nor stationary rotational movement.
In U.S. Pat. No. 4,149,735 is disclosed a skateboard with a pivot roller. A skateboard rider is thereby enabled to perform 360 degree rotations by shifting weight which tilts the board and engages a pivot roller. Lateral or circumferential movements are, however, not achievable therewith.
Ball bearings have been used as the prime support and locomotion means for the skates described in U.S. Pat. No. 1,616,442, U.S. Pat. No. 3,963,251 and U.S. Pat. No. 4,034,995. Primary support through ball bearings is undesirable. Discomfort arises because highly concentrated loads are placed on both the ball structure and on the supporting surface. Furthermore, skating is rendered inefficient because ball bearings provide no transverse reactive forces which normally permit skaters to propel themselves faster.
Consequently, it is an object of this invention to provide a roller disc assembly, that when in skate form, is foot comfortable and is capable of linear forward/backward, circumferential, lateral and stationary rotational movement.
Another object of this invention is to provide a skate with a roller disc assembly having the aforementioned freedoms of movement.
A final object of this invention is to provide a skate with a roller disc assembly additionally capable of toe pivot movement.